Building my own PM

[Daniele_Redivo]

Nomath here is a better graph of what you requested. X axis is overall time [us], Y axis is time between consecutive pulses [us]

[JaapvanE]

The problem is that u turns out too big. In fact, considering w = 90 rad/s (a value I measured while rowing smoothly, which seems reasonable), u becomes:
u = (184/2.8)^0.3333 * 90 = 363.13 m/s
which of course is too big. So, since 90 rad/s seems reasonable (I check the frequency of pulses with the oscilloscope just to be 100% sure and I got 9ms period, so 2*pi*1000/8/9 = 87rad/s, the problem is in k/c, I guess. What am I doing wrong?

The problem is that the drag you use shouldn't contain the 10^6 factor. That factor is only for presentation to the user, but should not be used in calculations.

[Daniele_Redivo]

Great, it now displays meaningful numbers. Tomorrow I will workout to test the "feeling" of the new numbers. The only problem is that I don't have any original PM to test my own PM against.
Here are some pictures, I still have to add buttons and several functions thou:






The curve plots the filtered k/time between each blade of the fan, where k is a constant good enough for having nice numbers to put on the graph.
I used 2xESP8266: one for irq tasks, which does most of the math and one to drive the display. The communication is done using ESPnow protocol. It works pretty well, I checked if IRQs interrupt each other, meaning the processor is too slow or software too heavy, but this does not happen.
Next steps are to add some function buttons to set workouts, add more calculations such as power, ecc. And also add a 3D printed case.